Lymphomes intracrâniens du sujet immunocompétent

Most of the intracranial lymphomas are primary cerebral lymphomas (PCL); the incidence of PCL has increased considerably over the past two decades. Most of them are diffuse large B cell lymphomas. In 20% of the cases, PCL is associated with an ocular lymphoma (uveitis). The neuroradiological presentation is often very suggestive, but the diagnosis must be confirmed by a cerebral biopsy or a positive cytology of the CSF or the vitreous. High dose methotrexate (MTX) based chemotherapy (CT) followed by whole brain radiotherapy (WBRT) is currently the standard treatment for PCL. Despite a high rate of response, recurrence is observed in most of the cases. The median survival with a combined treatment ranges from 3 to 4 years. In the elderly, CT alone as initial treatment is recommended. This approach seems useful to avoid RT and to reduce the risk of delayed neurotoxicity due to the combined treatment. Secondary cerebral lymphomas present the same clinical and radiological features than PCL, but they occur late in the course of the systemic lymphoma. Primary dural lymphoma is a rare disease that frequently mimics a meningioma, and that corresponds, in terms of histology, to a MALT lymphoma. Intravascular lymphoma is a systemic lymphoma with a high affinity for the CNS and the skin. The clinical and neuroradiological presentations (stroke-like presentation) are related to lymphocyte proliferation and occlusion of the lumen of small vessels. Intravascular lymphoma is associated with a poor outcome.